[PATCH v5 03/10] reset: Add Realtek basic reset support

[Yu-Chun Lin]

From: Cheng-Yu Lee <cylee12@xxxxxxxxxxx>

Define the reset operations backed by a regmap-based register
interface and prepare the reset controller to be registered
through the reset framework.

Signed-off-by: Cheng-Yu Lee <cylee12@xxxxxxxxxxx>
Co-developed-by: Yu-Chun Lin <eleanor.lin@xxxxxxxxxxx>
Signed-off-by: Yu-Chun Lin <eleanor.lin@xxxxxxxxxxx>
---
Changes in v5:
- Created drivers/reset/realtek/ directory and include/linux/reset/realtek.h.
- Extracted the common reset helpers:
 - Moved the source code to drivers/reset/realtek/common.c and
 - the header to include/linux/reset/realtek.h
- Renamed rtk_reset_bank to rtk_reset_desc.
- Added 'bits' member to rtk_reset_desc structure.
- Removed rtk_reset_get_id() and rtk_reset_get_bank() helper.
- Introduced rtk_reset_get_desc().
---
 MAINTAINERS                    |  1 +
 drivers/reset/Kconfig          |  1 +
 drivers/reset/Makefile         |  1 +
 drivers/reset/realtek/Kconfig  |  3 ++
 drivers/reset/realtek/Makefile |  2 +
 drivers/reset/realtek/common.c | 91 ++++++++++++++++++++++++++++++++++
 include/linux/reset/realtek.h  | 25 ++++++++++
 7 files changed, 124 insertions(+)
 create mode 100644 drivers/reset/realtek/Kconfig
 create mode 100644 drivers/reset/realtek/Makefile
 create mode 100644 drivers/reset/realtek/common.c
 create mode 100644 include/linux/reset/realtek.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 721356d4c02c..9419b0497e0b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22229,6 +22229,7 @@ L:	devicetree@xxxxxxxxxxxxxxx
 L:	linux-clk@xxxxxxxxxxxxxxx
 S:	Supported
 F:	Documentation/devicetree/bindings/clock/realtek*
+F:	drivers/reset/realtek/*
 F:	include/dt-bindings/clock/realtek*
 
 REALTEK SPI-NAND
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 7ce151f6a7e4..03be1931f264 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -398,6 +398,7 @@ config RESET_ZYNQMP
 
 source "drivers/reset/amlogic/Kconfig"
 source "drivers/reset/hisilicon/Kconfig"
+source "drivers/reset/realtek/Kconfig"
 source "drivers/reset/spacemit/Kconfig"
 source "drivers/reset/starfive/Kconfig"
 source "drivers/reset/sti/Kconfig"
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index fc0cc99f8514..4407d1630070 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -2,6 +2,7 @@
 obj-y += core.o
 obj-y += amlogic/
 obj-y += hisilicon/
+obj-y += realtek/
 obj-y += spacemit/
 obj-y += starfive/
 obj-y += sti/
diff --git a/drivers/reset/realtek/Kconfig b/drivers/reset/realtek/Kconfig
new file mode 100644
index 000000000000..99a14d355803
--- /dev/null
+++ b/drivers/reset/realtek/Kconfig
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config RESET_RTK_COMMON
+	bool
diff --git a/drivers/reset/realtek/Makefile b/drivers/reset/realtek/Makefile
new file mode 100644
index 000000000000..b59a3f7f2453
--- /dev/null
+++ b/drivers/reset/realtek/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_RESET_RTK_COMMON) += common.o
diff --git a/drivers/reset/realtek/common.c b/drivers/reset/realtek/common.c
new file mode 100644
index 000000000000..b9e3219dc8f7
--- /dev/null
+++ b/drivers/reset/realtek/common.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2019 Realtek Semiconductor Corporation
+ */
+
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/reset/realtek.h>
+
+struct rtk_reset_data {
+	struct reset_controller_dev rcdev;
+	struct rtk_reset_desc *descs;
+	struct regmap *regmap;
+};
+
+static inline struct rtk_reset_data *to_rtk_reset_controller(struct reset_controller_dev *r)
+{
+	return container_of(r, struct rtk_reset_data, rcdev);
+}
+
+static inline struct rtk_reset_desc *rtk_reset_get_desc(struct rtk_reset_data *data,
+							unsigned long idx)
+{
+	return &data->descs[idx];
+}
+
+static int rtk_reset_assert(struct reset_controller_dev *rcdev,
+			    unsigned long idx)
+{
+	struct rtk_reset_data *data = to_rtk_reset_controller(rcdev);
+	struct rtk_reset_desc *desc = rtk_reset_get_desc(data, idx);
+	u32 mask = desc->write_en ? (0x3 << desc->bit) : BIT(desc->bit);
+	u32 val  = desc->write_en ? (0x2 << desc->bit) : 0;
+
+	return regmap_update_bits(data->regmap, desc->ofs, mask, val);
+}
+
+static int rtk_reset_deassert(struct reset_controller_dev *rcdev,
+			      unsigned long idx)
+{
+	struct rtk_reset_data *data = to_rtk_reset_controller(rcdev);
+	struct rtk_reset_desc *desc = rtk_reset_get_desc(data, idx);
+	u32 mask = desc->write_en ? (0x3 << desc->bit) : BIT(desc->bit);
+	u32 val  = mask;
+
+	return regmap_update_bits(data->regmap, desc->ofs, mask, val);
+}
+
+static int rtk_reset_status(struct reset_controller_dev *rcdev,
+			    unsigned long idx)
+{
+	struct rtk_reset_data *data = to_rtk_reset_controller(rcdev);
+	struct rtk_reset_desc *desc = rtk_reset_get_desc(data, idx);
+	u32 val;
+	int ret;
+
+	ret = regmap_read(data->regmap, desc->ofs, &val);
+	if (ret)
+		return ret;
+
+	return !((val >> desc->bit) & 1);
+}
+
+static const struct reset_control_ops rtk_reset_ops = {
+	.assert   = rtk_reset_assert,
+	.deassert = rtk_reset_deassert,
+	.status   = rtk_reset_status,
+};
+
+int rtk_reset_controller_add(struct device *dev,
+			     struct rtk_reset_initdata *initdata)
+{
+	struct rtk_reset_data *data;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->regmap          = initdata->regmap;
+	data->descs           = initdata->descs;
+	data->rcdev.owner     = THIS_MODULE;
+	data->rcdev.ops       = &rtk_reset_ops;
+	data->rcdev.dev       = dev;
+	data->rcdev.of_node   = dev->of_node;
+	data->rcdev.nr_resets = initdata->num_descs;
+
+	return devm_reset_controller_register(dev, &data->rcdev);
+}
+EXPORT_SYMBOL_GPL(rtk_reset_controller_add);
diff --git a/include/linux/reset/realtek.h b/include/linux/reset/realtek.h
new file mode 100644
index 000000000000..3c2226e3ed26
--- /dev/null
+++ b/include/linux/reset/realtek.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_RESET_REALTEK_H__
+#define __LINUX_RESET_REALTEK_H__
+
+#include <linux/types.h>
+
+struct device;
+struct regmap;
+
+struct rtk_reset_desc {
+	u32 ofs;
+	u32 bit;
+	u32 write_en;
+};
+
+struct rtk_reset_initdata {
+	struct rtk_reset_desc *descs;
+	u32 num_descs;
+	struct regmap *regmap;
+};
+
+int rtk_reset_controller_add(struct device *dev,
+			     struct rtk_reset_initdata *initdata);
+
+#endif /* __LINUX_RESET_REALTEK_H__ */
-- 
2.34.1